<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			.box{
				width: 800px;
				height: 800px;
				border: 1px solid;
				display: flex;
				justify-content: center;
				align-items: center;
			}
			div{
				width: 200px;
				height: 200px;
			}
			.box div:nth-child(1){
				
			}
		</style>
	</head>
	<body>
		<div class="box">
			<div>1</div>
			<div>2</div>
			<div>3</div>
		</div>
	</body>
</html>
